Her own team produced a rival model, also in March, which speculated that as many as 50% of Britons may have already been infected with the virus.

Asked for her updated ratio, she said the epidemic had “largely come and is on its way out in this country”.

On Thursday the ONS published its second snapshot of people with coronavirus in the community in England, finding that 137,000 people – 0.25% of the population – had coronavirus at any given time during the two weeks from May 4-17.

She said: “The question is, should we act on a possible worst case scenario, given the costs of lockdown?

“It seems to me that given that the costs of lockdown are mounting, that case is becoming more and more fragile.”

Prof Gupta said it was possible that Britain could have fared better by doing “nothing at all” or by concentrating on protecting those most vulnerable to coronavirus.

“Remaining in a state of lockdown is extremely dangerous from the point of view of the vulnerability of the entire population to new pathogens,” she added.

“Effectively we used to live in a state approximating lockdown 100 years ago, and that was what created the conditions for the Spanish Flu to come in and kill 50m people.”